Question

183

Why is angular.isNumber() not working as expected?

rated 0 times [ 189] [ 6] / answers: 1 / hits: 27703 / 11 Years ago, thu, june 27, 2013, 12:00:00

It appears as if AngularJS's angular.isNumber is not working. It doesn't work with strings that are numbers. Am I doing something wrong? Should I just use isNaN()?

angular.isNumber('95.55') == false

angular.isNumber('95.55' * 1) == true

angular.isNumber('bla' * 1) == true

angular.isNumber(NaN) == true

I need something to see if a string is a number (when it actually is) and angular.isNumber() won't let me do that unless I multiply by 1, but if I do that then it will always be true. Also NaN is not a number (by definition) and so should return false.

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answered 11 Years ago ellisw · Accepted Answer

In JavaScript, typeof NaN === 'number'.

If you need to recognise a String as a Number, cast it to Number, convert back to String and compare this against the input, for example.

function stringIsNumber(s) {

    var x = +s; // made cast obvious for demonstration

    return x.toString() === s;

}



stringIsNumber('95.55'); // true

stringIsNumber('foo'); // false

// still have

stringIsNumber('NaN'); // true